Plastic or synthetic resin conduit assemblies made up of discrete extruded tubes, connected by webs and adapted to be folded or bent to form a compact tube bundle are known, for example, from German Patent 36 03 849.
In this construction, the synthetic resin tubes have rounded inner and outer peripheries and are adapted to be traversed by wires, conductors or like electrically conductive or optical elements hereinafter referred to generally as cables or cabling and adapted to be use in connections or power supply.
In the assembly of this patent, the individual tubes are formed with outer members providing the contact surfaces between the tubes when they are bundled, generally in the shape of triangular cross section cylinder segments so that the walls of these segments, forming the flat contact surfaces, extend generally radially of the tube bundle or assembly. The outer periphery of the assembly, defined by the contiguous arc-segmental outer walls of the segments, is generally cylindrical.
This construction of the assembly has several drawbacks. Firstly, the cylindrical segmental formations defining the contact surfaces contribute to the high cost of material of the assembly and fabrication problems.
Attempts to modify the construction have led to loss of stability and the inability of the assembly to withstand pressure, for example, from overlying earth when the assemblies are buried.
It has been proposed to utilize cylindrical tubes of sufficient wall thickness to overcome the latter drawback in conduit assemblies formed by tube bundles, but these have the drawback that the cylindrical peripheries of the tubes, when bundled, lie only in line contact with one another. To assure adequate stability of the assembly as a whole, therefore, it has been necessary to provide a supporting core around which the tubes are arrayed and which functions as a stiffening element.
Another problem with earlier tube bundle conduit assemblies, of course, is that these earlier systems required separate members for securing the tubes in their bundled configuration, thereby complicating the formation of the tube bundle configuration for use.